Off-shore pipelines, used to pump oil and gas ashore from off-shore drilling rigs and terminals, are required to be capable of withstanding very high internal pressures and temperatures and are therefore typically made of metals such as iron and steel.
However, among major issues encountered with metal pipelines in general, and on-shore and off-shore pipelines in particular, is the problem of corrosion due to the severe environment, which causes a deterioration of the material and, as a consequence, reduces its thermal and chemical resistance.
It is well known that coatings based on fluoropolymers, in particular vinylidene fluoride-based polymers, are advantageously resistant to these severe environment conditions on account of their chemical resistance to hydrocarbons and/or corrosive gases at temperatures typically between 100° C. and 160° C.
Also, it is well known that a primer is typically used in order to enhance adhesion of a fluoropolymer top coat to the metal pipeline.
However, despite the use of a primer, harsh conditions of high temperature and/or pressure, which coated metal pipelines are subjected to, in particular in the oil and gas industry, adversely affect the adhesion of the coating to the metal. Disbondment is typically caused by permeation of moisture or oxygen through the top coat. As a consequence, the primer becomes brittle and detachment of the coating from the metal can be observed, resulting in an increased corrosion of the same.